DIY leakdown test Questions

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04-10-2008, 04:50 AM
BadAss95-530i

DIY leakdown test Questions

Im sure some of this should be obvious and i *think* I know...but ...
For an m60 3.0l engine

1. Where is a suitable place to hand crank each cylinder to TDC?

The link http://www.geocities.com/dsmgrrrl/FAQs/leakdown.htm from Bruno's site says their was a slot in the drivers side wheel well. Is that true (or does this geocities site feature a random car?)

2. Instead of an air compressor, could i run compressed nitrogen?

I have no compressor, but i have abundant cheap access to nitrogen cylinders and can easily build a hose to go from a purging regulator to the quick connect of the leakdown tester.

3. Can i just hit the ground running or do i need to 'unhook' stuff?

I saw no mention of unplugging or disconnecting anything prior. No DME or Fuel pump relay disconnections (as a compression test calls for)?

Thanks in advance,
Terran
04-10-2008, 02:06 PM
whiskychaser

Quote:

Originally Posted by BadAss95-530i

Im sure some of this should be obvious and i *think* I know...but ...
For an m60 3.0l engine

1. Where is a suitable place to hand crank each cylinder to TDC?

The link http://www.geocities.com/dsmgrrrl/FAQs/leakdown.htm from Bruno's site says their was a slot in the drivers side wheel well. Is that true (or does this geocities site feature a random car?)

2. Instead of an air compressor, could i run compressed nitrogen?

I have no compressor, but i have abundant cheap access to nitrogen cylinders and can easily build a hose to go from a purging regulator to the quick connect of the leakdown tester.

3. Can i just hit the ground running or do i need to 'unhook' stuff?

I saw no mention of unplugging or disconnecting anything prior. No DME or Fuel pump relay disconnections (as a compression test calls for)?

Thanks in advance,
Terran

1. If you can crank your engine through a hole in the inner wing you have a problem. You should be looking for a big nut at the bottom of the block on the rad end. You will need to drop the sump guard to get at it properly
2. Using nitrogen may move the goal posts. I'd stick to air
3. For safety's sake I'd unplug the main and fuel pump relay (actually I wouldnt- I'd just get on with it but I think thats what you should do)
04-10-2008, 07:04 PM
pingu

Whiskychaser has a point about nitrogen maybe moving the goalposts but if it were me then, being lazy, I'd also use nitrogen if convenient. Air is 79% or so nitrogen so I don't think it would be far off the readings you'd get using air. It might even be exactly the same as air?
04-11-2008, 03:30 AM
BadAss95-530i

Quote:

Originally Posted by pingu

Whiskychaser has a point about nitrogen maybe moving the goalposts but if it were me then, being lazy, I'd also use nitrogen if convenient. Air is 79% or so nitrogen so I don't think it would be far off the readings you'd get using air. It might even be exactly the same as air?

Yeah thats what i was thinking. Using the regulator to step it down so that I would have only a 100psi consistantly in the cylinder seems to be the same as cranking a compressor up to 100psi in there...but maybe the compression rates of the two gases are diff which would throw off the flow % #s?
The key is I went ahead and got some air anyways. turned out to be no big deal. The stealer wants $400 for the leakdown. Ive got an indy who may squeez me tomorrow for a compression test at $60 but it looks to be about 60 bones for tools/guages/adaptors for me to just attempt the much more telling leakdown test myself in combination with items i already have. Still in the planning stages though...